Document and image scanners are pervasive in the modern digital world. They are used to digitize documents and images (e.g., pictures) so that they can be used electronically. One of the most common types of scanner is the fax machine. A physical document such as, for example, a typed document or picture, is fed into the scanner where it is automatically moved across a sensor to digitize visual content (e.g., printed text, illustrations, photo, etc) provided on the surface of the physical document, thereby creating a digitized image of the visual content. The digitized visual content image is then sent over a communication network to another fax machines that prints a representation of the digitized visual content image. A physical document is one example of a scannable object.
Another common type of scanner is the flatbed scanner, which is typically connected to a computer. A physical document is placed onto a glass imaging surface (commonly referred to as a platen) of the flatbed scanner and, once activated, the flatbed scanner automatically scans the visual content of the physical document, thereby creating a digitized image of the visual content. The digitized visual content image can then be sent the computer for allowing a user to view and/or use the digitized visual content image for any one of a number of purposes. Examples of such purposes include, but are not limited to, printing the digitized visual content image, editing the digitized visual content image, converting the digitized visual content image into an electronic text document using optical character recognition (OCR) software, inserting the digitized visual content image into an electronic document, and transmitting the digitized visual content image over a network.
The operation of such scanners generates captured image data (also referred to as image sensing data) and position indicating data (also referred to as position sensor data). The captured image data represents an image of visual content of a scanned object (e.g., a physical document) physical document that is captured by an image sensor of the scanner. The position indicating data corresponds to a relative position of the scanner when a corresponding portion of the captured image data captured. Combined, the captured image data and the position indicating data allow a complete digitized visual content image to be constructed. Scanners generally require a close tolerance between the captured image data and the position indicating data to accurately construct the digitized visual content image. The more accurate the position and sensor data, the better the image produced by the scanner. Likewise, without accurate position indicating data, the image can be blurred or smeared. However, because conventional scanners generally use mechanical systems to accurately secure and/or position physical documents relative to the position sensor and/or image sensor, their ability to maintain close tolerance between the sensor data and the position indicating data, thus adversely impacting image quality.
Various implementations of handheld scanners have been attempted. But, they have not been commercially or functionally successful. In operation, these conventional handheld scanners take a series of images as a user moves the scanner across a physical document. The series of images are then assembled into the final image based on position indicating data of each capture image.
A key drawback with most conventional handheld scanners is that the scanned image is of poor quality. There are many factors that, cumulatively, can cause poor image quality, of which a few are described here. One problem with most conventional handheld scanners is that the user has no way of knowing if they have completely scanned an entire area of the scanned object until the final image is viewed. If the user has not scanned a portion of the scanned object during the scanning process, the user must rescan the scanned object again with no re-assurance that they will not inadvertently scan a different portion of the scanned image, thus resulting in a poor user experience. Another problem with most conventional handheld scanners is that the position indicating data typically becomes more inaccurate as the errors in the position indicating data accumulate with the number of scanned tiles, thus resulting in an inaccurate image with blurring and other errors. Other errors in the scanned image can come from scratches in the camera lens, poor assembly of the individual tiles, and/or low image processing speed, which can all result in poor quality scanned images and/or a poor user experience.